In the case of this sentence we have an example of a Passive Voice Sentence:
The Hawaiian Islands are also known for their lush, exotic scenery
In which the verb phrase is are also known. “Also” in this case is just an adverb modifying the verb phrase. This last is compounded by the verb To Be in the present form and the perfective form of the main verb (know).
On the other hand, in this example of the passive, the Subject Phrase is The Hawaiian Islands which are the recipients of the action performed in the Verb Phrase by an unknown/covert agent which is not mentioned in this sentence.